Field of the Invention
The present invention relates to an article transport facility including: a transfer apparatus that receives and supplies an article; and a control unit that controls the transfer apparatus.
Description of the Related Art
JP 5800193B2 discloses an example of an article transport facility including: a transfer apparatus that receives and supplies an article from and to a fixed support portion that supports an article in a fixed state, while a moving support portion moves to protrude and retract; and a control unit that controls the transfer apparatus. This article transport facility is configured such that the control unit executes protrusion control upon a moving member reaching a protrusion start position as a result of stopping control. The protrusion start position is set upstream of a stop position in a direction in which the moving member moves. This technology contributes to improvements in transport efficiency because the execution of protrusion control is started before stopping control has been completed so that the transfer apparatus can complete the reception and supply of an article from and to the fixed support portion as early as possible.
In the case where protrusion control is started before stopping control has been completed as in this article transport facility, if there is a fixed support portion that is adjacent to a fixed support portion that is to receive or supply an article, in the direction in which the moving member moves, an interference-target object such as the adjacent fixed support portion or an article supported by the fixed support portion, and the moving support portion, interfere with each other. Such interference is a problem. Therefore, in this article transport facility, when the amount of movement of the moving support portion from the retracted position in the widthwise direction exceeds a predetermined amount after protrusion control has started, it is determined whether or not the moving member on the moving path has moved past an interference range in which the moving support portion and the interference object interfere with each other, and thereafter the protrusion control is continued.
In this article transport facility, whether or not the moving member has moved past the range in which the moving support portion interferes with the interference object is determined based on positional information regarding the moving member. In this article transport facility, whether or not the moving member has moved past the interference range is determined based on positional information regarding the moving member, and whether or not to continue the protrusion control is not determined by directly detecting the interference object or a structure around the interference object. Paragraph [0090] of JP 5800193B2 discloses that the moving support portion is provided with a presence sensor that detects the presence or absence of an interference object, and whether or not the moving member has moved past the range in which the moving member interferes with the interference object is determined based on detection information from the presence sensor. However, with the moving support portion in the state of being provided with the presence sensor, if an abnormality occurs in the moving support portion regarding the attachment state thereof, whether or not the moving member has moved past the range in which the moving support portion interferes with the interference object may be erroneously determined, and there is also the risk of the moving support portion interfering with the interference object.